Let's get to the headline breaking right now from former senior investigators, six of them of the mysterious crash of twa flight 800, 17 years ago off long island. Now, the six whistle-blowers are breaking their silence, saying the final report was falsified and the crash was not an accident. Abc's brian ross is here with the very latest this morning. Good morning, brian. Reporter: Good morning, elizabeth. The official cause of the explosion was determined to be a faulty fuel tank, not terrorism. But in a new documentary about to be made public, the former investigators claim the fbi and others covered up what really happened. And their theory, although unproven, is that a missile came the plane or hit it or exploded near it, shortly after it took off from kennedy airport. This theory had been vetted during the investigation. But former investigators, including a senior investigator for the national transportation safety board, alleged the fbi doctored the evidence. This is some of what he's saying in that documentary. There's a lot of search boats. One described a big fireball with pieces coming off of it. And the hangar had -- they set up video surveillance in my hangar. And found that three fbi agents from another office had entered the hangar for purposes unknown in the wee hours of the morning. Reporter: And that is what he has to say about it, claiming what apparently would have to be one of the largest cover-ups in the history of this country involving the fbi and every other major agency to hide the fact that a missile hit this plane. We both have been covering this story since it happened tragically, killing all those people. And there's long been rumors around that there was some sort of flash in the sky. A missile seen in the sky. Now, we have two accident investigators, but the chief medical examiner, the senior medical forensics examiner. It sounds like it got a decent cadre of people with reputations. Reporter: They have appealed to the families. Many of them were never satisfied with the explanation. A mundane explanation that it was a mechanical flaw, not a missile. But a lot of that has been disproved, covering this very closely. And this must have been some act of terrorism. I think it is not, my own view. But this new information will lead to a controversy being re-ignited and the claims that will have to be addressed by the government. And only once has the ntsb reopened an investigation like this. And that was way back in 1968. Chances not good? Reporter: Hard to say. This is going to be controversial. And a lot of the debate that had been settled. Brian, thank you so much.

This transcript has been automatically generated and may not be 100% accurate.

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